1. Saved Rachni
2. Saved Wrex
3. Saved the council put anderson, etc, etc. Paragon all the way.
4. Saved everyone in ME2, hooked up with Tali, Jack and Liara in the same save. Paragon all the way saved everyone destroyed base, etc. That save will never be deleted
5. Made Udina quit his embassy post

Man if my Rachni and Wrex choices made in ME1 results in a 30 second cutscene in ME3, I'm going to be hella pissed...

Having the Rachni and Krogan on your side while the biggest and bestest battle of all eternity (well, 50,000 years at least ) is waged, I'd be willing to bet that it'll involve a little more than a 30 second cutscene